Electric switch



Jan. 1, 1946.

A. G. ELMENDORF ELECTRIC SWITCH Filed April 4, 1944 2 Sheets-Sheet l Andrew G. Elmendcnf,

Inventor":

:JMA

His Attorne g;

Jan. 1, 19 16.

A. G. ELMENDORF ELECTRIC SWITCH 2 Sheets-Sheet 2 Filed April 4, 1944 Inventor: I AhdFW'G.E|mehdOTFs H is Attor-h e g- Patented Jan. 1,1946 I ELECTRIC SWITCH Andrew G. Elmendorf, Schenectady, N. Y... 9.3-. signor to General Electric Company, a corporation of New York Application. April 4, 1944, Serial No. 529,451

2. Claims.

My invention relates to electric switches, more particularly to electromagnetically operated electric switches of the type known as contactors, and has for its object a simple, reliable and shockproof operating mechanism for the switch.

In carrying out my invention in one form, I

provide operating means for the switch comprising an electrom'agnet having two plunger type armatures extending into an operating coil from opposite sides, which armatures are mechanically connected together by means of bell cranks. Secured to the bell cranks is a gear segment which operates a second gear, this second gear turning a crank connected to the pivoted switch arm. The mechanism is so constructed and arranged that the crank is in a dead center position when the magnet is deenergized and energized, and the switch in its open and closed circuit positions whereby the switch is secured against shock in each position.

For a more complete understanding of my invention, reference should be had to the accomarmatures are connected together to move in unison by means of two bell cranks 28 and 29 having their lower ends pivotally connected rcspectively to the armatures 26 and 21 and mounted on stationary pivots 30 and 31. At their other ends the two bell cranks are pivotally connected together by a movable pivot pin 32 carried by them.

A connection is' provided between the bell cranks and the switch arm structure i6 and i3 by means of a gear segment 33 secured to the ends of the bell cranks adjacent the pivot 32. As shown, this gear segment forms part of an extension secured on the end of the bell crank 28, the gear segment being adjacent the pivot pin 32. It will be understood that the slot connection is provided between the ends of the bell cranks and the pivot pin 32, this slot preferably, as shown in panying drawings, Fig. 1 of which is a front elevation view, partly in section, of a contactor embodying my invention showing the parts in circuit closed position; Fig. 2 is a side elevation view of the device shown in Fig. 1; Fig. 3 is a fragmentary front elevation view showing part of the mechanism in its open circuit position; while Fig. 4 is a fragmentary sectional view taken along the line 4--4 of Fig. 1.

Referring to the drawings, I have shown my invention in one form as applied to a switch hav; ing an arm structure pivotally mounted on pins and II secured to side supporting plates 12 and i3 which in turn are secured to a suitable metallic support or base i4. The switch arm structure comprises side links or arms 16 and I3 and having their lower ends mounted on the pivots i0 and H and, moreover. secured to'each other by a cross bar ll. The upper ends'of the bars and I6 are connected by pivot pins 18 and I9 to a second cross bar 20 carrying bridging con tact members 2|, 22 and 23. Thus movement of the arm structure about the pivot axis formed by the pins 16 and Ii moves the bridging members between closed and open circuit positions with respect to stationary contacts mounted on the support l4.

For operating the switch arm structure, I have provided an electromagnet comprising an operating coil 24 mounted in a magnet frame 26 and provided with two plunger type armatures 28 and 21 extending toward each other into opposite ends outwardly substantially at right angles with the arms I! and 16.

By means of helical springs 39 and 40 mounted on the pivot pins 30 and 3|, the two bell cranks 28 and 29 are biased respectively in clockwise and counterclockwise directions to move the switch arm structure to its open circuit position, i. e., counterclockwise, as viewed in Fig. 2, and the armatures 28 and 21 outward from the coil to their unattracted positions. In this position the bell cranks and armatures are brought to rest by the engagement of a stop projection 40a on the bell crank 29 with the supporting bracket 42.

As shown in Figs. 1 and 2, the switch arm is in its closed circuit position and the driving mechanism so arranged that the crank 33 is in a dead center position with respect to the link 31 at that time, i. e., the link 31 is substantially parallel with the crank. Thus the switch arm structure is held securely in its closed circuit position and is not affected by shocks since a shock force tending to move the switch arm to its open circuit position does not tend. to rotate the shaft 36 because of the dead center position of the crank 36.

. Another feature making the device free from shocks when in the closed circuit position is the arrangement of the plunger armatures so that their inner ends inside of the coil engage each other in abutting relation when moved to their attracted positions. Likewise, as shown in Fig.

0f t n and magnet n Th lu 3, when the magnet coil 24 is deenergized by position with respect to Fig. 1. In other words, the gear 34 is rotated counterclockwise substantially 180 degrees. This movement downward of the crank 36 moves the arm 38 and the switch arm structure in a counterclockwise direction, as seen in Fig. 2, to-its open circuit position.

Continuing with additional details of construction. the magnet is mounted on the supporting bracket 4! secured to the base l4, while the pivot pins 30 and 3! for the bell cranks are mounted in a supporting bracket 42 secured by bolts 43 and 44 to the upper side of the framework or flange 45 secured to each side of the magnet. This bracket has two upwardly extending side portions 42a and 42b which are substantially parallel. The pivots 80 and 31 extend through these side portions, and at their upper ends the side portions are provided with bearings for the shaft 85 which extends crosswise between them. The shaft '35 and the pivots 30, SI and 32 are parallel with each other. v

In order to provide for freedom of movement, a bearing pin 46 having a spherical surface is provided on the outer end of the arm 38 for the upper end of the link 31. This is required because of the fact that the crank 36 is mounted on edges of the strap 38 are cut away, as indicated by the reference numerals 59 and 5D, to provide the required freedom of movement laterally for th link 31. g

The stationary contacts are mounted on a plate or base 5| made of electrically insulating material, which base is in turn secured to the support I4 by suitable bolts. As shown, three pairs of stationary contacts are provided with which cooperate respectively the bridging members 2l, 22 and 23. Each pair, as shown in Fig. 2, consists of a stationary contact 52 mounted in the bottom of a cup 53 of heat refractory electrically insulating material. The stationary contact 52 is suitably electrically secured as by welding to a cross conducting plate 56 at the bottom, as seen in Fig. 1, which plate is in turn secured mechanically and electrically by screws 55 and 56 to a terminal conducting plate 51. This terminal plate 51 is in turn secured to the insulating base 55 by a screw 58. A similar construction is provided for the other stationary contacts. Electrical connections for each pair of stationary contacts are made with the connection strap 51.

The movaible contacts 59 are secured on the ends of rods or bars 80, the other ends of which are secured to the respective bridging members, the rods 60 being long enough to extend downward to the bottom of the insulating cup 53 and bring the movable contact into engagement with the stationary contact when the switch arm is moved v to its closed circuit position.

An interlock switch is provided adjacent the arm 8| consisting of two leaves pivoted on a bracket 62 .secured to an insulating support 63. The upper end of the switch arm extends into an aperture 84 (Fig. 1) in a bracket 88 made of electrically insulating material secured in turn to the bell crank 29. Thus. as the bell crank moves about its pivot 3|, the switch arm BI is moved about its pivot between the upper ends of two conducting plates 56 and 81 to which electrical connections maybe made. As shown in Fig. 1, the switch arm is in contact only with the upper .end of the strap 87, and therefore the two straps are electrically disconnected from each other. When the bell crank 29 moves counterclockwise, as seen in Fig. 1, about its pivot 3|, the switch arm 6| is moved clockwise about its pivot so that its lower end extends between the upper ends of the two straps 68 and 61 and closes a'circuit between them.

A guide plunger 68 is secured at each end of the movable cross bar 20. Each guide plunger 68 extends through an opening provided for it in the insulating plate El and is slidably movable in this opening. These guide plungers provide for rectilinear movement of the bridging members 2 I, 22 and 23 toward and away from their stationary contacts. As previously pointed out, the cross bar 20 carrying the bridging members is connected by pivots is and IE to the side arms to and it. Each bridging member is provided with a central aperture through which extends a pin es secured to. the cross bar 20. The bridging member is biased against the cross bar by a helical spring 16 encircling the pin 68 and having its outer end in engagement with a flanged washer H on the outer end of the pin 69. The spring 10 yields somewhat upon engagement of the contacts and thereby assures a predetermined contact pressure.

It will be observed that I have provided a very compact and efiicient operating mechanism. This mechanism comprises a coil mounted on the support with its center line substantially parallel with the support, and pivots I B and II for the switch arm 38 defining a pivot axis parallel with the support. on the other hand, the shaft 35 is mounted for movement about an axis lying in the plane of movement of the switch arm 38 and substantially perpendicular to the support. -By means of the link 31 and the spherical bearing G6, I connect the switch arm 38 with the crank pin 36 for movement of the switch arm 38 by the crank pin.

I also provide simple and reliable means for securingthe coil 24 in place in the magnet frame 25. The magnet frame is rectangular in shape.

In fact, it is substantially square as shown and includes two U-shaped core members, upper and lower members as seen in Fig. 1, which form upper and lower magnetic paths between the ends of the plunger armatures 26 and 21. The upper and lower U-shaped core members are clamped between metal plates, only one of which is shown in Fig. l, by means of suitable rivets 12 extending through them, each of these clamping plates being provided with a supporting flange 45. On the ends of the coils are plates 13 and 14 made of a molded electrically insulating material on each of which is provided a pair of spaced projections extending outwardly axially of the coil. Only one of these projections for each plate is shown in Fig. 1, this being the pro- J'ection 15 for the plate 13 and the projection 16 for the plate 74. The other projection for each of the plates 13 and H is behind the one shown in Fig. 1 in spaced relation therewith and on the asearse a being shown in Fig. 4. Thus the pair of projections at each end of the coilembrace thetwo clamping plates of the magnet core at that point and hold the coil in position in the rectangular opening oi the magnet. i. e., against movemint in a direction transverse to the axis of the co 1. l

'I also provide a metal positioning member 11, Fig, 1, provided with projections Ill and d9 which embrace thev projection 15 on that end of the 6011; This member has an L-shaped cross section, as shown in Fig. 4. It is secured to the frame 45 together with a plunger guide 19a by means of a screw 80 extending through the frame and extending'through a tapped hole in the centerm the member 11. Thus the projections it and I8 engage opposite sides of the projection 15 on the coil and secure the projection between them. An oppositely disposed member 8| (F1 4), identical inconstruotion with the member 11, cooperates with the projection lid on the opposite side of the coil. Furthermore, the projections 15 andi'l ic are provided each with a portion extending under the member 1'1 or 8!. In other words, the projections 'extend toward the left hand as seen in Fig. 4 under the members I1 and 81 so that the members I1 and 81 secure the coil against movement transversely or its axis in an upward or downward direction as seen in 3 Fig. 4. Thuethe members 11 and Si secure the coil gainst movement transversely of its axis.

1 have also provided a resilient connection for securing the coil comprising a spring strip 83 (Figs. 1 and 4) which extends parallel with the member ll. Screws 84 and 85 extend through the frame and bear on opposite ends of the spring 83 whereby the center of the spring is forced against the rounded end of the projection .15, as shown in Fig. 1. Thus the coil is resiliently pressed toward the right hand, as viewed in Fig. 1. A similar strip spring 88 (Fig. 4) is provided on the opposite side of the magnet frame at the left-hand end. On the right-hand end of the. coil no spring strips are provided although two forked securing members similar to the members TI and 8| are provided, the construction bein the same as previously described for theopposite end of the coil. Thus the coil is secured against severe shocks.

While I have shown a particular embodiment 'of'my invention, it-will be understood, of course,

that I do not wish to be limited thereto since many modifications may be made, and I therefore contemplateby the appended cla to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electric switch comprising a support, a magnet coil mounted on said support with its axis substantially parallel with said support, a layer provided with a pivot on said support having its axis substantially perpendicular to said support,

an armature for said coil mounted on said lever, 05

a gear segment secured to said lever, a shaft mounted on said support in substantial perpendicular relation with said support, a gear on said shaft meshing with said gear segment, a crank pin on said shaft extending substantially parallel with said shaft, a switch arm mounted on said support for movement on a pivot substantially parallel with said support, said switch arm moving in a plane passing through the axis of said shaft, a bearing pin on saidswitch arm extendhis lengthwise of said switch arm and having a partly spherical bearing surface, a link having one end connected to said crank pin for pivotal movement on said crank pin and having its other end connected to said spherical'bearing surface for operation of said switch arm about its pivot when said crank pin is turned by said shaft, spring means for biasing said lever and said 'armature to their unattracted positions with said crankpin in one dead center position, said coil when ener ized turnin said crank pin to its opposite dead center position, and switch means operated by said switch arm.

2. An electric switch comprising a support, two

bell crank levers mounted on spaced apart stationary pivots secured to said support with first cranks are caused to move in unison about said pivots,a magnet coil mounted on said support 'betweensaid second arms with its center line substantially parallel with said support, a pair of plunger 'armatures extending into opposite ends of said coil connected respectively to said second '1 arms, a gear segment secured to one of said first 40 arms at a point adjacent said pivotal connection between said first arms, a shaft mounted on said support in substantial perpendicular relationwith said support, a gear on said shaft meshing with said gear segment, a crank pin on said shaft extending substantially parallel with said shaft, a switch arm mounted on said support for.

movement on a pivot substantially parallel with said support, said switch arm moving in a plane passing through the axis of said shaft, a bearins pin on said switch arm extending lengthwise of said switch arm and having a partly spherical bearing surface, a link having one and connected to said crank pin for pivotal movement on said crank pin "and having its other endconnected to said spherical bearing surface for operation of said switch arm about its pivot axis when said crank pin is turned by said shaft, spring means for biasing said bell crank levers and said arma- 'tures to their unattracted positions with said crank pin in one dead center positioh, said coil -when energized turning said crank pin to its opposite dead center position, and switch means operated by said switch arm.

ANDREW c+. ELlViENDORF. 

